Good to Know

Aunt or uncle tests (also called ‘avuncular tests’) can show if someone is the biological nephew or niece of an aunt or uncle. Testing providers need a cheek swab sample from the nephew or niece, and from the ‘alleged’ aunt or uncle. These samples are then compared to see if there’s a genetic match.

These tests are mainly used when an ‘alleged’ parent is not available for testing, and so a biological relationship with that parent’s family can be proven using a sample from the ‘alleged’ aunt or uncle instead.

On purchasing, the provider will send you a testing kit with everything you need to take the samples. You can take the samples at home and after you send the kit back, they’ll be in touch with the results a few days later. You can choose how you are contacted, with email generally being the quickest service. Some providers offer express services but these often come with extra fees.

Look out for companies selling cheap kits. That’s exactly what they are – just the kit and no testing. Providers then charge more to actually run the test when you return the samples.

’Peace of mind’ or ‘legal’ test?
There are two types of service for aunt or uncle testing: ‘Peace of mind’ tests and ‘legal’ tests – legal tests are court admissible. The science behind the tests is exactly the same – the difference is that for court admissible tests, somebody official needs to watch them being taken so the court is assured that the samples came from the right people. Court admissible tests also require that the samples be handled securely all the way to the lab.

Are the tests accurate?
The tests are accurate, but not as accurate or as straightforward as paternity testing because the child is less closely related to his or her aunt or uncle. The tests compare DNA from both parties at certain ‘DNA locations’ to establish a genetic match. Most providers check 16 locations, some check up to 68 which improves the accuracy but which costs more.

To help get a more accurate result, many providers allow you to test the ‘known’ parent of the child as well. This helps the provider to exclude 50% of the child’s DNA (the half which came from the known parent) so they can focus on establishing a match with the ‘alleged’ parent.

Different testing providers use different ways to express accuracy. Some will say they can test at a certain percentage accuracy, some will use an ‘avuncular index’ where anything above ‘1.0’ indicates a biological relationship, and below ‘1.0’ indicates no biological relationship.

Testing a nephew against an uncle – Y chromosome testing
If you’re testing a nephew against his ‘alleged’ uncle, and that uncle is the brother of that nephew’s ‘alleged’ father; the test can be conducted with a greater degree of accuracy. Males have a Y chromosome that is passed from father to son, so if the nephew has the same Y chromosome as his uncle, a biological relationship is proven.

What if the family members to be tested live far apart?
Some providers allow you to have the different parts of the test sent separately to those providing samples. All the kits are labelled so they can be matched back at the laboratory.

Watch out for VAT and hefty postage being added at the checkout. Some providers with offices in the UK will use labs overseas, so if having your samples tested in the UK is important to you (and the provider’s website isn’t clear) check out our listings for these details.